1. Technical Field
The present invention relates to a vehicle curtain airbag device.
2. Related Art
Vehicle curtain airbag devices are known wherein, in the event of a side-on collision, a curtain airbag is inflated and deployed along a side window from a vehicle width direction outside end portion of a roof headlining, thereby protecting the head of a seated occupant (see for example Japanese Patent Application Laid-Open (JP-A) No. 2008-006895, JP-A No. 2012-096780, JP-A No. 06-239195, JP-A No. 2007-153224, JP-A No. 2001-055108, and JP-A No. 2008-284904).
In the above, JP-A No. 2008-006895 discloses technology wherein a curtain airbag is configured with an end portion side inflation portion formed as a separate chamber to the vehicle front side of a general inflation portion, with the end portion side inflation portion partitioned from the general inflation portion by a partitioning portion. A rear end portion of a tension cloth that couples together the general inflation portion and a front pillar is joined to the partitioning portion. According to this configuration, during inflation and deployment the end portion side inflation portion is pushed out towards the vehicle width direction inside by the tension cloth, bearing and arresting the head of a seated occupant that is moving under inertia towards the vehicle diagonal front outside in the event of an oblique collision.
JP-A No. 2012-096780 discloses technology wherein a curtain airbag is provided with a front chamber to the vehicle front side of an inflation region, the front chamber partitioned from the inflation region by a seam portion. A cloth shaped position retention portion is provided at the vehicle width direction inside of the front chamber and a main chamber of the inflation region. According to this configuration, the position retention portion retains the front chamber in a state further towards the vehicle width direction inside than the main chamber in the event of for example a rollover. As a result, the distance between the head of a seated occupant and the front chamber can be reduced, enabling early restraint of the head of the seated occupant.
However, although the technology disclosed in JP-A No. 2008-006895 may be expected to be effective in an oblique collision, there is room for improvement from the perspective that it is difficult to also achieve occupant protection in the event of a rollover. In the technology disclosed in JP-A No. 2012-096780, there is room for improvement with respect to what are referred to as small overlap collisions, that have recently been the focus of attention, of collisions with a barrier disposed at the vehicle width direction outside of a front side member. Namely, in the event of a small overlap collision the driver attempts to move under inertia towards the vehicle diagonal front outside. Depending on such factors as the position of the seat, it is conceivable that the head of the driver could move under inertia into a gap between a driver's seat airbag and the curtain airbag, an issue to which no particular consideration is given in the technology disclosed in JP-A No. 2012-096780.
In consideration of the above issues, an object of the present invention is to obtain a vehicle curtain airbag device capable of both securing occupant protection performance in the event of a rollover and securing occupant protection performance in the event of a small overlap collision.